All filenames should be case-insensitive

All filename paths should be normalized to use the same case, because there are case-insensitive relationships: Data/Libs/Subsumption/Platforms/PU/System/Stanton/stantonsystem.xml includes Filename="pu\system\stanton\stanton4.socpak" while the file is: <scdatatools.p4k.SOCPak file=<scdatatools.p4k.P4KExtFile name='Data/ObjectContainers/PU/system/stanton/stanton4.socpak' mode='r'> mode='r'>